Prior art microstrip array antennas for use in point-to-point communications, with cell-site stations and with long-range communications applications, suffer from poor performance in the areas of beam width, sidelobes and impedance matching. Specifically, prior art microstrip array antennas do not optimally match each radiator element and waste RF power by using a terminating resistor at the end of the traveling wave antenna, which results in a loss of the RF power applied to the antenna, rather than the radiation of that RF power. Also, prior art microstrip array antennas do not achieve a high level of sidelobe control while producing a narrow beam width.
The present invention, on the other hand, optimizes radiator element design, improves impedance matching and sidelobe patterns and provides better phase coherence across the array, which enables a narrow beam width with low sidelobes and improves efficiency by eliminating the terminating resistor used in prior art designs. Thus, the antenna of the present invention is a traveling wave microstrip array antenna which produces a narrow beam width and low sidelobes at 39 GHz, provides better impedance matching and produces an efficient antenna array at microwave/millimeter frequencies including Ka-band (26.5-40.0 GHz) and above.